Lager's mystery ingredient found

Missing ancestor of yeast used in cold-brewed beer is identified

Lager beers got their start in Bavaria, but it was a little South American spice that really kicked things off.

Scientists have known for decades that a hybrid species of yeast, Saccharomyces pastorianus, is the microbe that ferments lagers. It’s also well known that one parent of S. pastorianus is the common baking and brewing yeast Saccharomyces cerevisiae. But the other parent of lager yeast has eluded scientists, who have scoured Europe and North America looking for it.

Turns out they were looking in the wrong hemisphere. An inter

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